A computational framework for the structural analysis of a superelastic cardiac valve stent

During the last decade an increasing number of patients is subjected to heart surgeries and minimally invasive procedures are becoming more common: among those procedures, TAVI has gained enormous popularity and its implementation has become common practice. For this reason, the need of advanced tools to optimize and develop the devices used in such procedures has become more and more evident: one of those tools is finite element analysis. The aim of this work is to define a computational framework that can analyze a nitinol (Ni-Ti) stent for TAVI applications in terms of its mechanical performances and comparing them with corresponding experimental verification tests. Starting from the CAD design provided by the developers at the host company, the simulations of the manufacturing processes needed to form the stent are implemented; next, its core mechanical characteristics are evaluated through the simulation of its crimping and the simulation of the device migration. After that the loading of the stent into the catheter, its deployment from it and its recapturing after partial deployment are simulated. Finally, the device response to cyclic loading after the implantation is analyzed and a fatigue assessment is performed. The framework was verified with experimental tests and showed great potential for analyzing and optimizing the stent design.